1. Field of the Invention
The present invention encompasses a building component used to make permanent concrete form walls and, more particularly, an insulated concrete form system comprising a plurality of side panels having connecting elements formed therein, in which the connecting elements are coupled by a wire ladder.
2. Background Art
Concrete walls in building construction are most often produced by first setting up two parallel form walls and pouring concrete into the space between the walls. After the concrete hardens, the builder then removes the form walls, leaving the cured concrete wall.
This prior art technique has drawbacks. Formation of the concrete basement walls is inefficient because of the time required to erect the forms, wait until the concrete cures (typically three to seven days), and take down the forms. This prior art technique, therefore, is an expensive, labor-intensive process.
Accordingly, techniques have developed for forming modular concrete walls, which use a foam insulating material. The modular form walls are set up parallel to each other and connecting components hold the two form walls in place relative to each other while concrete is poured therebetween. The form walls, however, remain in place after the concrete cures. That is, the form walls, which are constructed of foam insulating material, are a permanent part of the building after the concrete cures. The concrete walls made using this technique can be stacked on top of each other many stories high to form all of a building's walls. In addition to the efficiency gained by retaining the form walls as part of the permanent structure, the materials of the form walls often provide adequate insulation for the building.
Although the prior art includes many proposed variations to achieve improvements with this technique, drawbacks still exist for each design. The connecting components used in the prior art to hold the walls are constructed of (1) plastic foam, (2) high density plastic, or (3) a metal bridge, which is a non-structural support, i.e., once the concrete cures, the connecting components serve no function. For example, one embodiment of a connecting component is disclosed in U.S. Pat. No. 5,390,459, which issued to Mensen on Feb. 21, 1995 and which is incorporated herein by reference. This patent discloses "bridging members" that comprise end plates connected by a plurality of web members. The bridging members also use reinforcing ribs, reinforcing webs, reinforcing members extending from the upper edge of the web member to the top side of the end plates, and reinforcing members extending from the lower edge of the web member to the bottom side of the end plates. As one skilled in the art will appreciate, this support system is expensive to construct, which increases the cost of the formed wall.
Another disadvantage of prior art devices is that reinforcement of the concrete is necessary because the connecting components provide no structural strength after the concrete cures. Reinforcing steel, known as "re-bar," is normally placed in the cavity between the form walls before pouring the concrete. The re-bar provides horizontal structural integrity to the cured concrete, thereby making "reinforced concrete." The re-bar may be secured to the component holding the two foam panels together. For example, the bridging members in U.S. Pat. No. 5,390,459 are provided with a series of hooked structures to support the re-bar. Thus, in the prior art, not only is there a cost for the connecting component, but also an additional expenditure for the steel re-bar when used.